Fuse for projectiles



2 Sheets-Sheet l X v y April 24, 1934. 'N. E. METHLIN FUSE FOR PROJECTILES Filed Feb. 23 1933 Ari] 1934. N. E. METHLIN FUSE FOR PROJECTILES Filed Feb. 25, 1933 2 Sheets-Sheet 2 Patented Apr. 24, 1934 FUSE FOR PROJECTILES Nicolas Emilien Methlin, Paris, France, assignor to Schneider & Cie, Paris, France, a company of France 6 Claims.

This invention relates to an improvement in percussion fuses of the Well-known type in which the percussion mechanism is constituted by a movable casing containing the whole of the mechanism and normally fixed relatively to the fuse body by means of one or more looking members such as pins.

According to the invention, the well-known system above referred to is so arranged that the member or members locking the movable casing, for instance the locking pin, are exposed, on the shot being fired, to the action of inertia of the percussion system (movable casing or possibly casing and the support of the casing) but only to a given extent which can be regulated, this action of inertia of the movable casing and possibly also of its support producing, in the conditions in question, a strain on the locking members, without however this 0 strain or decrease of resistance being sufficient to bring about their breaking.

A smaller effort is thus required at the impact for breaking the locking member or members, which means an increase of sensitiveness of the fuse in working, the locking member or members retaining their full strength up to the moment of firing.

In patent application No. 658,186 filed on the same date as the present patent application and having for its title Improvements in fuses for projectiles, the applicant has described and illustrated a system of percussion fuse with which the same results are obtained, but in that case, it is a question of a fuse which does not possess a percussion mechanism mounted in a movable casing.

For obtaining the said result with the fuse of the type above referred to, the percussion system and its locking member or members are carried according to the present invention by an element the position of which is adjustable relative to a safety device which becomes withdrawn at the end of the acceleration, and which forms at the same time a stop or abutment for the percussion system on firing the shot. The adjustment of the element carrying the percussion system allows of a small inward movement of the percussion system on the firing of the shot, with the result that under the action of inertia of the said percussion system. the locking member is strained without however being broken.

Several constructions according to the invention are illustrated by way of example in the accompanying drawings.

Figures 1 to 6 relate to a first construction.

Figures 1 and 2 show the fuse in longitudinal section through the axis, in the position which the parts occupy before the shot is fired, and in the position at the end of the acceleration respectively.

Figure 3 is a sectional plan on line III-III of Figure 1.

Figure 4 shows separately in elevation the movable casing of the percussion system.

Figure 5 is a plan of the winged washer used with this system, and

Figure 6 shows separately in elevation one of the elements of the centrifugal safety device with which the said system is combined.

In this construction, the percussion system of the well known type is constituted by a casing a in which are arranged the striker or needle I) and the percussion cap 0. The casing a, is provided with windows or recesses 01, with which engage the wings h of a washer It provided with a central hole b (Figure 5). These wings rest in front against inner projections 01 of the head element at of the fuse body de. In the present construction the casing a is secured by a pin 7 to the fuse body which comprises according to the invention an element d which can be secured in a variable position to the complementary element 6 for the purpose of regulating the distance a: between the shoulder a of the casing a and one of the elements of the centrifugal safety device.

The latter is constituted by a sleeve 1' and segments g of a well known type held against the sleeve by a binding 9 the sleeve 1 pressing in the position of rest on the said segments by means of a collar I under the action of a spring f one end of which rests against lugs or projections d engaging with two diametrically opposite slots f of the said sleeve.

In the position of rest, when the parts are in the position indicated in Figure 1, the element (1 of the fuse body, screwed into the element e, is locked for instance by means of a screw 2 in such a position as to leave a given 109 distance a: between the shoulder a of the casing a and the edge of the sleeve j". This distance is such that when the shot is fired, the inertia of the movable casing can act on the pin 7' by which the casing a is secured to the element d of 105 the fuse body.

The recoil of the casing under the action of inertia, towards the interior of the element cl and of the recess f of the sleeve 1 constituting the conduit for the transmission of fire, de- 110 is screwed into the fuse body 6.

forms the pin 5/. But as the distance a: is sufii ciently small, such a deformation of the pin, shown exaggerated in Figure 2, whilst starting the shearing, cannot produce breaking even under the pressure of the air acting on the casing a. As soon as, under the action of inertia, the casing has covered the distance at, it will press with its shoulder 11 against the front edge of the sleeve 1 which is prevented from making any movement inward by the segments g which become withdrawn only after the acceleration is finished. Figure 2 shows the position which the parts occupy when, after the acceleration is finished, the segments g have moved apart under the action of centrifugal force, which allows an inward movement of the sleeve f under the pressure of the spring I pressing against the projections al In this position the sleeve 1 forms in a well known manner an obstacle to any accidental return of the segments 9 which have been moved apart.

On meeting an obstacle'and the casing striking the latter, the shearing of the pin is completed, and the working of the mechanism takes place in the well known manner.

It will be seen that the construction described provides a simple and efficacious means for increasing the sensitiveness of the well known fuses of the type comprising a percussion system constituted by a movable casing. containing the whole of the mechanism. a

The sensitiveness of the fuse on impact can be increased whilst retaining for the locking member 7' before working a strength equal to that which is given to it in well known fuses of the type under consideration, owing to the fact that at the moment of impact the locking member is in a strained or weakened condition.

Besides, the combination of the percussion system with the centrifugal safety device and the possibility of adjusting the distance between the percussion system and a centrifugal element forming a stop/makes it possible to limit 'very strictly and to any desired extent the degree of strain to be placed on the locking member 7' during the flight of the projectile and before it meets an obstacle. I Figure 7 shows another construction in longitudinal section. In this construction the percus.

sion system, in other words, the movable casing abch', is locked by a pin 7' .to a tubular part This tubular part is provided with windows k with which engage the extended endsof the wings h of the washer h-h and the tube forms in its upper part a guide for the casing, and at the same time its rear part forms a conduit for the transmission of fire. The position of the whole, tube 2c and the percussion system secured to it by pin 7, 60

is fired, is determined in the present construction by the distance between the head of the striker a and the front edge of one of the elements f of the centrifugal safety device f-g. As indicated in Figure '7, the element 1 is interposed between the fuse body and the tubeic which is thus guided by the said sleeve 1, and the latter is pressed against the segments 9 by a spring resting also against a sleeve m which in a well known manner forms an additional safety device preventing any accidental movement apart of the segments 'g during the acceleration. V 7

On the shot being fired, the sleeve m moves inwards and comes in a well known manner into the path followed by the segments g in moving apart. Again on the shot being fired, the inertia of the percussion system abc will also act on the pin 9' until the moment when the enlarged head of the striker a meets the front edge of the sleeve f. At the end of the acceleration, the sleeve m is driven forwards under the action of the spring f and releases the segments 9 which are moved apart by centrifugal force, which enables the sleeve 1 to be driven rearwards by the spring F. The mechanism is thus cooked, and its locking pin j has undergone a limited reduction of strength on the shot being fired, as in the preceding construction.

' Figures 8 to 11 show a modified construction of Figure 7 applied to; a fuse of the type of those described and illustrated in U. S. Letters Patent to Remondy, No. 1,854,669, the parts similar to those of Figure .7 being marked with the same reference letters. The only difference between this construction and that of Figure '7 is to be.

seen in the fact that the percussion system, in other words the movable casing containing the whole of themechanism, instead of being secured by a pin to the tube is of adjustable position is supported by a thimble a :which is secured tothe said tube by a pin 7'. Moreover, the spring is. not enclosed by the additional safety sleeve m, but the latter could be used also in the present constructioniif desired. Figure 8 shows the parts in the position of rest, and the working indicated in Figures 9 and 10 which are. partial sectionssimilar. to that of Figure 8, showing the parts respectively in the position which they occupy. after the acceleration is finished when the centrifugal safety device has-acted, and at the moment of meeting an obstacle such as the skin of an-aircraft wing. It has been assumed in this figure that. the fuse has been combined in a well known manner with a cap 0 built in accordance with U. S. Letters Patent to Remondy;

between the enlarged head of the casing and Q the front edge of the sleeve f is adjusted by a relative movement between the tube and the bottom element e of the fuse body, that is to say exactly as in the previous example. 011 the shotbeing fired, the percussion system with the thimble supporting the same, act by their inertia on the pin 9', until the moment when the enlarged headof the casing strikes the front edge of the sleeve Any direct action of the air on this percussion device is hindered by the cap 0 built in such a manner that it can bend under the pressure of the air without exerting, a thrust on the movable casing. The centrifugal safety device becomes Withdrawn in, the well known,

small strength such'as for instance the skin p of an aeroplane wing, the fuse acts by driving in of the front element in the well known manner, the parts assuming at the moment of the percussion the position indicated in Figurelo.

in all the constructions described, the locking of the movable casing has been assumed to be done by means of one pin only. It goes without saying that nothing would be changed in the described combination if the locking were done by a plurality of similar members, and the same would apply if the locking member instead of being a pin, were constituted by the flange or lugs of a disc secured in any suitable manner to the casing or forming support for the latter, the said flange or lugs being let in the fuse body.

I claim 1. A percussion fuse for projectiles comprising a fuse body adapted to be connected to a projectile, a percussion mechanism including a casing axially movable with respect to said fuse body and relatively movable striker and percussion cap members housed within said casing, means for normally retaining said casing and members in a fixed position relative to said fuse body including a supporting element secured to said fuse body and a yieldable retaining element securing said percussion mechanism to said supporting element, safety means for positively preventing movement of said striker and percussion cap members into striking position until after the projectile has been fired, said means being so constructed and arranged as to permit a relatively small axial movement of said percussion mechanism relative to said supporting element at the instant of firing due to the inertia thereof, said movement being limited by said safety means to an amplitude sufficient to deform and materially weaken said retaining element but insuificient to reduce its resistance below that necessary to balance the forces encountered in normal flight, and means for adjusting the position of said supporting element relatively to said fuse body and safety means whereby the extent of deformation of said retaining element upon firing may be predeterminedly adjusted and the sensitivity of the fuse upon impact thereby varied.

2. A percussion fuse for projectiles comprising a fuse body adapted to be connected to a projectile, a percussion mechanism including a casing axially movable with respect to said fuse body and relatively movable striker and percussion cap members housed within said casing, means for normally retaining said casing and members in a fixed position relative to said fuse body including a supporting element secured to said fuse body and a frangible pin passing through both said percussion mechanism and said supporting element, centrifugally actuated safety means for positively preventing movement of said striker and percussion cap members into striking position until after the projectile has been fired, said means being so constructed and arranged as to permit a relatively small axial movement of said percussion mechanism relative to said supported and the sensitivity of the fuse upon impact thereby varied.

3. A percussion fuse for projectiles comprising a fuse body adapted to be connected to a projectile, a percussion mechanism including a casing axially movable with respect to said fuse body and relatively movable striker and percussion cap members housed within said casing, means for normally retaining said casing and members in a fixed position relative to said fuse body including a supporting element secured to said fuse body and a frangible pin passing through both said casing and said supporting element, a sleeve axially movable relative to said supporting element and fuse body and forming a conduit for the transmission of fire from said percussion cap member to the projectile, centrifugally actuated safety means for positively preventing axial movement of said sleeve until after the projectile is in flight, a shoulder on said percussion mechanism, said safety means and sleeve being so constructed and arranged as to leave a relatively small space between one end of said sleeve and said shoulder when said ele ments are in normal position, whereby at the instant of firing said percussion mechanism is permitted a limited axial movement relative to the supporting element, said movement being limited by said sleeve to an amplitude sufiicient to deform and materially weaken said frangible pin but insufiicient to fracture the same, and means for adjusting the position of said supporting element relatively to said fuse body and sleeve whereby the extent of deformation of said pin upon firing may be predeterminedly adjusted and the sensitivity of the fuse upon impact .A thereby varied.

4. A percussion fuse for projectiles comprising a fuse body adapted to be connected to a projectile, a percussion mechanism including a casing axially movable with respect to said fuse body and relatively movable striker and percussion cap members housed within said casing, means for normally retaining said casing and members in a fixed position relative to said fuse body including a supporting element threaded to and forming the nose portion of said fuse body and a frangible pin passing through both said casing and said supporting element, a sleeve axially movable relative to said supporting element and fuse body and forming a conduit for the transmission of fire from said percussion cap member to the projectile, centrifugally actuated safety means for positively preventing axial movement of said sleeve until after the projectile has been fired, a shoulder formed on said percussion mechanism, said safety means and sleeve being so constructed and arranged as to leave a relatively small space between one end of said sleeve and said shoulder when said elements are in normal position, whereby at the instant of firing said percussion mechanism is permitted a limited axial movement relative to the supporting element, said movement being limited by abutment with said sleeve to an amplitude sufficient to deform and materially weaken said frangible pin but insuflicient to fracture the same, and means for locking said supporting element to said fuse body in a plurality of adjusted positions relative to said fuse body and sleeve whereby the extent of deformation of said pin upon firing may be predeterminedly adjusted and the sensitivity of the fuse upon impact thereby varied.

5. A percussion fuse for projectiles comprising a fuse body adapted to be connected to a projectile, a percussion mechanism including a casing axially movable with respect to said fuse body and relatively movable striker and percussion cap members housed within said casing, means for normally retaining said casing and members in a fixed position relative to said fuse body including a tubular supporting element securedto said fuse body and forming a conduit for the transmission of fire from said percussion cap member to the projectile and a frangible pin passing through both said casing and said supporting element, a sleeve axially movable relative to said supporting element and fuse body, centrifugally actuated safety means for positively preventing axial movement of said sleeve until after the projectile is in flight, both said sleeve and safety means surrounding said tubular supporting element, a shoulder formed on said percussion mechanism, said safety means and sleeve being so constructed and arranged as to leave a relatively small space between one end of said sleeve and said shoulder when said elements are in normal position, whereby at the instant of firing said percussion mechanism is permitted a limited axial movement relative to the supporting element, said movement being limited by said sleeve to an amplitude sufficient to deform and materially weaken said frangible pin but insufficient to fracture the same, and means for adjusting the position of said supporting element relatively to said fuse body and sleeve whereby the extent of deformation of said pin upon firing may be predeterminedly adjusted and the sensitivity of the fuse upon impact thereby varied.

6. A percussion fuse for projectiles comprising a fuse body adapted to be connected to a projectile,

a percussion mechanism including a'casing axially movable with respect to said fuse body and relatively movable striker and percussion cap members housed within said casing, means for normally retaining said'casing and members in 1a fixedposition relative to said fuse body includ-- ing a tubular supporting element housed within and threaded to said fuse body, a thimble axially movable within said element on which said casing is supportedand a frangible pin passing through said thimble and said supporting element, a sleeve axially movable relative to said supporting element and fuse body, centrifugally actuated safety means for positively preventing axial movement of said sleeve until after the projectile is in flight, a shoulder formed on said percussion mechanism, said safety means and sleeve being so constructed and arranged as to leave a relatively small space between one end of said sleeve and said shoulder when said elements are in normal position, whereby at the instant of firing said percussion mechanism is permitted a limited axial movement relative to the supporting element, said movement being limited by abutment with said sleeve to'an amplitude suflicient to deform and materially weaken said frangible pin but insufficient to fracture the same, and means for looking said supporting element to said fuse body in a plurality of adjusted positions relative to said fuse body and sleeve whereby the extent of deformation of said pin upon firing may be predeterminedly adjusted and the sensitivity of the fuse upon impact thereby varied.

' NICOLAS'EMILIEN METHLIN. 

